/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.coders;



import com.bff.gaia.unified.sdk.values.TypeDescriptor;



import javax.annotation.Nullable;

import java.io.InputStream;

import java.io.OutputStream;



/** A {@link Coder} for {@link Void}. Uses zero bytes per {@link Void}. */

public class VoidCoder extends AtomicCoder<Void> {



  public static VoidCoder of() {

    return INSTANCE;

  }



  /////////////////////////////////////////////////////////////////////////////



  private static final VoidCoder INSTANCE = new VoidCoder();

  private static final TypeDescriptor<Void> TYPE_DESCRIPTOR = new TypeDescriptor<Void>() {};

  private static final Object STRUCTURAL_VOID_VALUE = new Object();



  private VoidCoder() {}



  @Override

  public void encode(Void value, OutputStream outStream) {

    // Nothing to write!

  }



  @Override

  @Nullable

  public Void decode(InputStream inStream) {

    // Nothing to read!

    return null;

  }



  @Override

  public void verifyDeterministic() {}



  @Override

  public Object structuralValue(Void value) {

    return STRUCTURAL_VOID_VALUE;

  }



  /**

   * {@inheritDoc}

   *

   * @return {@code true}. {@link VoidCoder#getEncodedElementByteSize} runs in constant time.

   */

  @Override

  public boolean isRegisterByteSizeObserverCheap(Void value) {

    return true;

  }



  @Override

  public TypeDescriptor<Void> getEncodedTypeDescriptor() {

    return TYPE_DESCRIPTOR;

  }



  @Override

  protected long getEncodedElementByteSize(Void value) throws Exception {

    return 0;

  }

}